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Biomedical subjects

K Olgaard

Publications and source records attributed to K Olgaard.

At least 91 records · Page 5Linked to original sources
PubMed1979

Influence of age on the endocrine-metabolic response to surgery.

The pathogenesis of the increased operative risk in elderly patients is unknown. From a theoretical point of view, a change in endocrine-metabolic response might be involved. In the present study, a battery of hormonal and metabolic variables were measured in eight young and eight elderly healthy males undergoing elective inguinal hernial repair under general anesthesia. Blood was drawn before induction of anesthesia, at skin incision, and one, two, and six hours after skin incision. The findings were: 1) Plasma cortisol increase was significantly higher in elderly than in young controls. 2) Plasma renin level was lower in old age, but renin-aldosterone and electrolyte response patterns were alike in the two groups. 3) Thyroid parameters, in terms of serum T4, serum T3, serum rT3, and T3-resin uptake, responded normally to surgery and showed no age-related differences. 4) The hyperglycemic response was not significantly influenced by age indicating unchanged glycoregulatory mechanisms also verified by determinations of plasma catecholamines, cAMP, and insulin. 5) Blood lymphocyte count was constantly lower in elderly than in young and decreased with time, but the age-related difference was not significant. 6) Blood polymorphonuclear leukocytes showed an increase of the same magnitude in both age groups, although at a significantly slower rate in the elderly. It is concluded that age affects some aspects of the initial endocrine-metabolic response to surgery.

Adult↗
PubMed1979

Epidural analgesia inhibits the renin and aldosterone response to surgery.

Renin activity and aldosterone concentration in plasma and excretion of sodium and potassium in urine were measured during a period of 24 hours in 12 patients undergoing hysterectomy under general anaesthesia or epidural analgesia. Analgesia extended from T4 to S5 and was effective throughout the study. The normal stress-induced increase in plasma renin activity and aldosterone was inhibited by epidural analgesia. Urinary excretion of potassium was significantly lower in the epidural group, but sodium and water retention showed no difference between groups. It is concluded that neurogenic stimuli from the surgical area are important release mechanisms of the renin-aldosterone response to surgery. The results suggest that post-operative sodium retention is caused by factors other than the mineralocorticoid system.

Adult↗
PubMed1979

Fluid and electrolyte absorption and renin-angiotensin-aldosterone axis in patients with severe short-bowel syndrome.

In eight patients who had received long-term parenteral nutrition because of short-bowel syndrome the need for parenteral supply of fluid, sodium, and potassium was estimated by balance studies. Six patients had jejunostomies. In two, most of the colon was preserved. Jejunostomy patients had a huge stool mass (1710--5270 g, median 2530 g/day) with fixed concentrations of sodium (92 +/- 10 mmol/l) and potassium (15 +/- 4 mmol/l). In contrast, two patients with massive small-bowel resection but with more than half of the colon intact showed almost normal sodium absorption and considerably smaller stool mass (170--510 g/day). Despite apparently good health and normal plasma electrolytes, urea, and haematocrit, four of six jejunostomy patients were sodium-depleted with low plasma volume, low sodium excretion in the urine, and increased plasma renin activity and, in the three most severe cases, increased aldosterone. Even in case of sodium depletion the sodium loss from jejunostomy effluents remained high and presumably unaffected by salt-retaining hormones. The study confirms the importance of preservation of part of the colon for maintenance of fluid and electrolyte balance in patients with extensive bowel resection. Jejunostomy patients who are eating normally may need large parenteral saline supply. Assessment of water and electrolyte homeostasis in these patients requires determination of the urinary sodium excretion and is supported by measurements of plasma renin activity and plasma aldosterone concentration.

Adult↗
PubMed1979

Hormonal response to volume depletion in non-nephrectomised patients on regular haemodialysis.

The hormonal response to volume depletion by isolated ultrafiltration has been studied in seven non-nephrectomised haemodialysis patients. The mean reduction in blood volume was 14%, and pulmonary artery wedge pressure reduction averaged 77%. No increments in heart rate were observed in any of the patients. Cardiac output decreased while systemic vascular resistance increased. Mean arterial blood pressure remained stable in all but two patients. Significant increments in plasma vasopressin concentration were only found during hypotensive episodes, while in the whole group no significant increase was found. Both plasma renin activity, plasma aldosterone and plasma cortisol increased significantly during isolated ultrafiltration. The moderate increase in systemic vascular resistance indicates that the peripheral sympathetic nervous system - at least partly - was functioning. It was, however, not correlated with changes in any of the measured hormones. Furthermore the adrenal and cardiac response appeared to be absent.

Aldosterone↗
PubMed1979

Scintigraphic skeletal changes in non-dialyzed patients with advanced renal failure.

Technetium-99m-polyphosphate (Tc-PP) bone scintigraphy was performed in 51 patients with advanced renal failure in order to evaluate the applicability of this method in detection of metabolic bone changes in these patients. The creatinine clearance varied from 2 to 40 ml/min and none of the patients had previously been on dialysis treatment. The scintigrams were graded according to the focal and the generalized abnormal uptake of the tracer in the skeleton. 34 patients showed generalized scintigraphic changes and among these the changes in 18 patients were classified as severe. An inverse correlation was found between the kidney function and the generalized scintigraphic classification. Focal bone changes were found in 11 patients. In order to evaluate the influence of the lack of kidney function on the scintigraphic results, 3 patients with acute oliguric renal failure were examined. All had normal scintigrams. It is concluded that Tc-PP bone scintigraphy is a sensitive method in revealing renal osteodystrophy in non-dialyzed patients with advanced renal failure in agreement with previous reports on patients on chronic hemodialysis and after kidney transplantation.

Adolescent↗
PubMed1978

Inhibition of aldosterone response to surgery by saline administration.

The renin-angiotensin system, ACTH and hyperkalaemia are known to induce increased plasma levels of aldosterone. In order to assess the relative significance of these mechanisms during surgical stress, aldosterone, cortisol and electrolytes in plasma were measured in 12 otherwise healthy women during and after cholecystectomy. The patients received either isotonic sodium chloride or 5 per cent glucose in water during the experimental period of 22 h. The results showed that the pronounced increase of aldosterone and the concomitant decrease of sodium in plasma found in patients given glucose in water could almost be inhibited by the administration of saline. Cortisol and potassium concentrations were identical in the two groups of subjects. It is concluded that the aldosterone response to surgery is mainly mediated via the renin-angiotensin system. This response is probably due to a reduced sodium content or volume of extracellular fluid, since it could almost be inhibited by administration of sodium chloride. The rationale of saline restriction during and after surgery is questioned.

Adult↗
PubMed1978

Has vitamin D a direct renal effect on the tubular reabsorption of phosphate? A study in parathyroidectomized (PTX) and non-PTX man.

The effect of 1-alpha-hydroxycholecalciferol (1alpha-OH-D3) on the renal handling of phosphate and the immunoreactive parathyroid hormone in serum (i-PTH) has been studied in 10 patients with a wide range of glomerular filtration rate (GFR), maximal tubular reabsorption of phosphate (TmP) and i-PTH. The patients were treated with 2 microgram 1alpha-OH-D3 per day for approximately 80 days. Before and after this period of treatment, the TmP, i-PTH, 51Cr EDTA clearance, extracellular volume, standard bicarbonate, and serum calcium were measured in each patient. The TmP/GFR ratio was used as an index of the renal handling of phosphate. The index increased significantly (mean 26.5%, p less than 0.01) during the treatment, while i-PTH decreased significantly (mean 37.0%, p less than 0.01). A significant inverse correlation was demonstrated between the TmP/GFR index and i-PTH both before (r = -0.87; p less than 0.001) and after (r = -0.79; p less than 0.01) the administration of 1alpha-OH-D3, while none of the other factors investigated were correlated to the index. This may suggest that the stimulating effect of biologically active vitamin D on the tubular reabsorption of phosphate is mediated via the parallel suppression of PTH, but does not exclude that biologically active vitamin D exerts a direct effect on the human renal tubule. Therefore, the effect of 1alpha-OH-D3 was studied in 5 totally parathyroidectomized patients, in whom concomitant suppression of PTH would not occur. Estimation of TmP/GFR was performed 1) when the patients were vitamin D depleted and hypocalcemic, and 2) after 14-27 days of treatment with 1alpha-OH-D3 to obtain stable normocalcemia. In patients with absent parathyroid function, no increasing effect of 1alpha-OH-D3 on TmP/GFR could be demonstrated. It is therefore concluded 1) that 1alpha-OH-D3 exhibits no antiphosphaturic effect in the absence of PTH and 2) that the previously demonstrated antiphosphaturic effect of 1alpha-OH-D3 in man is mediated via a concomitant suppression of PTH.

Absorption↗
PubMed1978

Calcium-dependent aldosterone secretion in anephric and nonnephrectomized patients on regular hemodialysis.

The present study was undertaken to investigate the effect of a continuous calcium infusion on the plasma levels of aldosterone, renin activity, and cortisol in six anephric and four nonnephrectomized patients on regular hemodialysis. In both groups, a significant increase in whole blood ionized calcium (b-Ca2+) was demonstrated. A significant increase in plasma aldosterone (PAC) was noted in the nonnephrectomized patients, in whom the rise in PAC correlated with the increase in b-Ca2+. However, in the anephric patients only a smaller and insignificant increase in PAC was found. No significant changes were demonstrated in plasma cortisol or renin activity, nor in potassium or sodium concentrations in either group. It is concluded that ionized calcium influences the plasma levels of aldosterone in uremic patients on regular hemodialysis.

Adrenocorticotropic Hormone↗
PubMed1978

Cessation of bone loss in chronic renal failure by 1-alpha-hydroxyvitamin D3: a controlled trial.

The study was undertaken in patients with chronic renal failure (CRF patients) in order to evaluate 1) the degree and course of skeletal demineralisation and 2) the effect on the bone mineral content (BMC) of long-term treatment with 1alpha-hydroxyvitamin D3 (1alpha(OH)D3). BMC was measured on the radius by 241 Am-photonabsorptiometry and the results were corrected for age, sex and bone width. In a cross-sectional study BMC was measured in 191 normal subjects and in 88 renal patients. In a controlled longitudinal trial 22 CRF patients were treated for 25.6 months with 1alpha(OH)D3, while 22 CRF patients did not receive vitamin D supplements. In CRF patients an accelerated bone loss (approximately 3%/year) and a significantly reduced BMC (mean 87.2% of normal) was found. In the 1alpha(OH)D3 treated patients BMC increased on an average 0.9%/year. This was significantly different from the continued bone loss recorded in the non-treated control patients. The data indicate that 1) CRF patients develop reduced bone mass because of accelerated bone loss; 2) cessation of this bone loss may be achieved by long-term treatment with 1alpha(OH)D3.

Adult↗
PubMed1977

The maximal tubular reabsorption of phosphate in relation to serum parathyroid hormone.

The relation between the renal handling of phosphate and the serum concentration of immunoreactive parathyroid hormone (i-PTH) was investigated in 15 patients with a very wide range of i-PTH, glomerular filtration rate (GFR), maximal tubular reabsorption of phosphate (TmP) and TmP/GFR-ratio. The latter was used as an index of the renal handling of phosphate. Seven patients had well functioning kidney allografts (GFR 43.1-64.9 ml/min), while 8 had varying degrees of chronic nephropathy (GFR 2.3-26.7 ml/min). The TmP, i-PTH, 51Cr EDTA clearance, the extracellular volume and serum concentrations of calcium and standard bicarbonate were estimated. An inverse significant correlation was demonstrated between TmP/GFR and i-PTH (p less than 0.001), while none of the other investigated factors correlated thyroid hormone has a key role in the regulation of the tubular handling of phosphate in patients with impaired renal function.

Adult↗